Division of Cerebral Integration

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Studies on Higher Function in Human Brain Using Neuroimaging Techniques

The goal of Division of Cerebral Integration is to understand the physiology of human
voluntary movement and other mental processing including language and social interaction using noninvasive functional neuroimaging technique, mainly fMRI. In particular, neural mechanisms of the social interaction is the main interest is the main focus of our research activities. Hyper-scanning fMRI (3T) has been installed to evaluate two individuals as one neural network during social interaction, and 7T MRI is now being installed to evaluate the detailed structures of the neural network . Multimodal approach including EEG , MEG , TMS ,and NIR is considered when appropriate.

Figure 1. Brain areas commonly activated by social and monetary rewards. Why are we nice to others? One answer provided by social psychologists is because it pays off. A social psychological theory stated that we do something nice to others for a good reputation or social approval just like we work for salary. Although this theory assumed that social reward of a good reputation has the same reward value as money, it was unknown whether it recruits the same reward circuitry as money in human brain. In this study, we found neural evidence that perceiving one’s good reputation formed by others activated the striatum, the brain’s reward system, in a similar manner to monetary reward. Considering a pivotal role played by a good reputation in social interactions, this study provides an important first step toward neural explanation for our everyday social behaviors.

Figure 2. Activation in a sighted (upper row) and blind subject (bottom row) during tactile discrimination tasks similar to reading Braille. The primary and association visual cortices of the blind are activated bilaterally (bottom row) whereas no such activation in the sighted. Only pixels with significant increase in cerebral blood flow during the task were superimposed on surface-rendered high resolution MRI. This is an example of cross-modal plasticity of human brain due to early visual deafferentation and/or longterm training of Braille reading. Depicted by functional MRI using high Tesla (3T) machine.